Work-Types of Work

The measurement of the energy of an object when it is displaced from its place by the action of an external force is known as the work. Work is defined in science as a force that causes an object to move. It is the scalar product of the applied force and the displacement caused by this force in the case of a constant force. Although both displacement and force are vector values, work is a scalar quantity due to the nature of scalar products. We frequently need to measure the work done by a moving object.

What is work?

Work is one of the essential processes in our daily life and science. There are various examples of work done in our day-to-day life. For example, an ox pulling a plough in a piece of land, a man pushing a cart in a mall, a student putting his school bag on his shoulder, and many more.

In general, work requires the application of a force that causes the thing to move. Displacement of the item is required for the task to be done; otherwise, science states that no work will be completed even if the force is applied. Suppose a person exhausts himself by pushing the wall after some time. He will feel completely tired, and no work will be done because the wall hasn’t moved from its place.

According to the standard definition, “the multiplication of the object of force in displacement’s direction with a magnitude of the displacement will give the value of the work done. Mathematically,

W = Fd cosθ

• W represents the work done by force.
• F represents the force applied.
• D represents displacement caused by the force
• θ represents the angle between the force and displacement vector.

Hence, in the same direction when θ became zero,

W = F.d

Unit of Work

The SI unit of the work is the joule (J). 1 Joule is defined as work done by force of 1 newton in displacing a particle for a single unit distance (1 unit metre) in the direction of the force. Work formula is used to compute work done, force, or displacement in any problem. It is written as in Newton metre or Nm.

What are the different types of work?

1. Positive Work: Positive work occurs when an object is displaced by force acting in its direction. The motion of an object falling towards the ground, where the object’s displacement is in the direction of gravity, is an example of this type of work.
2. Negative Work: Work is considered negative when the force and displacement are in opposite directions. For example, if an object is thrown upwards, its displacement will be upwards, while the force due to gravity will be downwards.
3. Zero Work: If the force and displacement directions are perpendicular to one another, the force on the item does not work. When we push forcefully against a wall, the force we are putting on the wall produces no work because the wall’s displacement is d = 0. On the other hand, our muscles use our internal energy in this process, and as a result, we become exhausted.

Factors affecting the work

Force: Force is described as a pull or push which could impact the speed and acceleration of any mass particle. The direction and magnitude of the force are classified as vector quantities. If the force applied on an item is nil or zero and doesn’t matter whether the particle is static or dynamic, the force will not work.

Displacement: It is a vector quantity that shows the smallest or shortest path between an object’s starting and final positions of a particle.

Difference between the concept of Daily Life Work and Scientific Work

Ram is studying for his upcoming exam. He conducts extensive research, creates diagrams, solves difficulties, and learns lessons. According to scientific definitions, he is incredibly “dedicated” to his studies, yet he only accomplishes a minimal amount of work.

Consider the following examples to understand the scientific concept of work better:

• A young youngster vigorously pushes against a wall. Despite the boy’s best efforts, the wall remains immovable. The boy is completely exhausted. Even though there is no relocation, there is no work done.
• A female stands still for a few hours with a big load on her head. She is fatigued from using so much effort to stand with the load on her back. According to the scientific definition of work, there hasn’t been any work done here because the load hasn’t moved.

Conclusion

In the above chapter, we have discussed the definition, SI unit, formula, and examples of the work. We have also read about the different types of work. The Positive and Negative Work is also an example of the work. When the displacement is in the opposite direction as the applied force, the work done by the force is negative. Let’s look at an example to better understand the concept, i.e. the difference between negative and positive effort. A man pulls a 5-kilogram box to a 10-metre height. In this case, the box is affected by a man’s force and gravitational force mg.

• A man applies the upward direction of the force.
• The gravitational pull is directed downward.
• The displacement is in an upward direction.